Many butterflies, moths, and other insects easily probe and identify potable liquids with their proboscises. The butterfly proboscis has a two-level pore hierarchy as illustrated in FIG. 1. The proboscis is nanoporous in its lateral dimension, which comprise the first level of pore hierarchy. These nanopores are created by overlapping legulae. The legulae are formed like a fence on two tubular musculature structures known as galeas. In FIG. 1 is visible the central groove with the legulae (shown by the arrow) looking like a fence at the dorsal side of the proboscis. The liquid wicks into the food canal through the nanopores formed by two nearest legulae. Galea tubes have lateral semi-cylindrical indentations, so that when galeas are locked by legulae, these two indentations form the food canal. The food canal, whose diameter ranges from a few to tens of micrometers, forms the second level of pore hierarchy. Thus, the proboscis can be considered as a drinking straw with a nanosponge.
The ability to manipulate the proboscis, which can be coiled and uncoiled like a party noisemaker, is closely linked to its remarkable fluid transport capabilities. In addition, the proboscis can be flawlessly positioned in a targeted liquid drop. Insect proboscises feature integrated sensors and filters that distinguish foods and multiple different chemicals. Integrating all of these features—ability to deploy, sense and sample, and identify low-volume fluids—into a single micro-nanofluidic device is attractive and promising for many engineering applications.
The basic concept of electrostatic spinning (or electrospinning) a polymer to form extremely small diameter fibers was first patented in the early twentieth century. Electrostatically spun fibers and nonwoven webs formed therefrom exhibit very high surface areas and can be formed from a wide variety of polymers and composites. These materials have traditionally found use in filtration applications, but have begun to gain attention in other industries, including in nonwoven textile applications as barrier fabrics, wipes, medical and pharmaceutical uses, and the like.
What is needed in the art is an artificial, biomimetic probe that possesses many properties of the natural proboscis. In addition, what is needed is an industrially scalable method of formation that can provide reproducible wetting, wicking, and mechanical characteristics for the probes thus produced. Precision control of these properties as is found in the natural proboscis would be of great benefit.